Automatic train-control system of the permissive type



Jax-1. 14, 1930. N. D. PRESTON AUTOMATIC TRAIN CONTROL SYSTEM OF THE PERMISSIVE TYPE Filed NOV. 27, 1925 -2 Sheets-Sheet l mundo/c Jan. 14, 1930. N. D. PRESTON AUTOMATIC TRAIN CONTROL SYSTEM OF THE PERMISSIVE TYPE,

Filed Nov. 27. 1925 2 Sheets-Sheet 2 .wat :avm E.

NAVE

Patented Jan. 14, 1930 UNET a? STATES NEIL I). PRESTON, OF ROCHESTER, NEW

inten YORK, ASSIGNOR TO GENERAL RAILWAY SIGNAL COMPANY, OF ROCHESTER, NEW YORK AUTOMATIC TRAIN-CONTROL SYSTEM 02 THE` PER-MISSIVE TYPE Application led November Thisinvention relates to an automatic train control system, and more particularly concerns a train control system embodying means for providing a certain degree of automatic 5 restrictive control for train operation over sections of trackway which are not equipped for train control operation.

In applying an automatic train control system to a railway, the wayside control equipment is frequently applied to a portion of the railway system only, the branch lines, sidings and such other sections of the trackway over which the trafiic conditions are not congested being left unequipped for train control operation. It is, ofcourse, sometimes necessary to operate certain locomotives or other vehicles, which are equipped for train control operation7 overthe unequipped sections of trackway; and in train operation in such non-train-control territory, as it is called, it is considered desirable to provide some form of restrictive control.

It is evident that an engineer who has been operating an equipped train over trackway equipped for train control operation will, to a certain extent, depend or rely upon such aparatus for a certain degree of protection, and that his vigilance and alertness in his observance and recognition of the indications of the wayside signals in unequipped territory may be weakened by his habitual reliance on the protection afforded by the automatic controL In any case, it is evident that a varying amount of protection should be afforded to train operation in a system having certain portions of its trackway equipped and other portions unequipped for train control operation.

With the above and other considerations in mind, it is proposed in accordance with the present invention to provide a system of train control in which a certain restrictive control is imposed upon the operation of an equipped train in unequipped or non-train-control territory, and, more specifically, it is proposed to provide car-carried apparatus incorporating a manually operable device which must be operated at predetermined successive time intervals While the train is traveling over unequipped Sections of trackway, the proper 27, 1925. Serial No. 71,661.

operation of this device acting to prevent the initiation of an automatic brake application.

It is further proposed to provide a system of automatic train control in which, in addition to requiring the engineer to perform an acknowledging` act at predetermined time intervals while traveling over unequipped sections of trackway, he is also required to acknowledge at the same predetermined time intervals while proceeding under unfavorable tralfic conditions in equipped sections of trackway, as in an occupied or danger block, unless he has moved the engineers brake valve to the service position, or has made a predetermined service brake application, a single manually operable acknowledging device being used for both purposes.

It is further proposed to provide a novel device which acts when operated to maintain a circuit closed for a predetermined limited time interval only, and which can not be manipulated to maintain such circuit closed for more than such time interval without repeated operation, this device being incorporated with suitable car-carried control apparatus to give the above mentioned restrictive control in unequipped territory and under unfavorable traffic conditions in equipped territory.

Other objects, advantages and characteristic features of the invention will become apparent as the description thereof progresses.

In describing the invention in detail, reference will be made to the accompanying drawings in which Fig. 1 shows in a simplified and diagrammatic manner the car-carried and trackway apparatus of a train control system embodying the present invention; and

Fie'. 2 shows the car-carried apparatus of a modified form of the invention in which successive acknowledgment is required under unfavorable traiiic conditions in equipped sections of a trackway, as well as under all trafiic conditions in unequipped sections.

In the particular embodiment chosen to illustrate the invention, a system of the well known continuous inductive train control 0f the two-position type has been shown, it being understood that the invention might be applied to any other train control system in which apparatus is provided for train operation in non-train-control territory.

Referring more particularly to the forni of the invention shown in Fig. 1, the track rails 1 have been shown divided into blocks by the insulating joints 2, the block I, a portion of the block H, the excess energy section J, and a portion of the block K having been shown. In order to simplify the disclosure, like reference characters having distinctive exponents have been used to designate the corresponding elements and devices used in the various blocks. The usual track relays 3 have been shown connected across the track rails at the entrance end of the blocks, the current for operating these relays being supplied by the track batteries 4 connected across the track rails at the exit end of each block. The secondary winding of a transformer 5 is connected across the track rails at the exit end of each block in series with the track battery 4, the primary winding of this transformer being supplied with alternating current of a suitable frequency from the transformer 6 connected across the transmission line 7, this circuit being completed through the contact fingers 8 and 9 and the front contacts of the track relay 3 of the next block in advance, the circuits being obvious from the drawings. Reactance coils 10 are connected in series with the transformer 5, these coils being` for the purpose of limiting the track phase control current in a manner Well known in the art.

From a study of the trackway equipment described above it will be seen that when a train is located in a given block, say the block I, its wheels and axles will shunt the current from the track battery 4, as well as the train control current from the transformer 5, from the track rails, thus preventing the flow of train control current in the track rails of the block I behind a train and causing the deenergization of the track relay 3 at the entrance end of this block. De-energization of the track relay 3 will cause the retraction of its contact fingers 8 and 9, thus cutting oil' the train control current from the track rails in thc first block H in the rear of the occupied block.

The insulated section of the track rails, designated as the excess energy section J, is supplied with alternating current of train control frequencyrthrough the transformers 11 and 12 and a circuit which is obvious from the drawings, the current supplied to this section being appreciably greater than that supplied to the usual blocks in train control territory. In order that the train control currents flowing in the track rails of the block I, which is assumed to be the last normal block in a section of trackway equipped for automatic train control, may

reflect tratiic conditions ahead, an alternating current track relay 13 is connected across the track rails at the entrance end of the excess energy section J, this relay together with the track relay 31 at the entrance end of the first block K in unequippcd or non-train-control territory, acting to control the energization of a line relay 111. The line relay 111- controls the encrgization of the transformer 5, supplying train control current to the track rails of the block I, so that the presence of a train in the excess energy section J or in the block K will cause the de-energization of the line relay 14, thus causing the train control current to be cut off from the track rails in the block I and giving the proper restrictive control.

Referring now more particularly to the car-carried apparatus of F ig. 1, a railway vehicle has been represented in the block H by the wheels and axles 15, the normal direction of traffic being indicated by the arrow. Suitable inductive receiving coils 16 and 17 of the well known type are mounted in front of the leading axle of the vehicle and in inductive relation to the track rails, these coils being connected to an amplifier A through a circuit which is tuned to resonance at the train control frequency by the condenser 18, this circuit being obvious from the drawing. The connection of the receiving coils 1G and 17 is such that voltages induced therein by alternating currents flowing in opposite directions in the track rails will be cumulative. The amplifier A may be of any type suitable for train control practice such as the audion tube type, and serves to amplify the voltages induced in the receiving coils 16 and 17. The output circuit of the amplifier A is connected to a main relay MR through a resistance unit 19.

The car-carried equipment also includes a non-control relay NC, preferably of the direct current type. A non-control button NB is provided, acting through suitable contact fingers 20 and 21 to close one circuit and to open another when it is actuated. rIbis noncontrol button NB is preferably located at some convenient point in the vehicle cab witlr in easy access` of the engineer.

In the operation of a vehicle equi ppcd for automatic train control, it is sometimcf's necessary because of the failure of certain parts of the equipment to render the brake applying apparatus inactive so that the train may proceed over the equipped or unequipped sections of trackway without restriction. In the present case, this emergency has been provided for by the cut-out contactor CC. This coutactor comprises a suitable manually operable switch which is preferably enclosed in a locked or sealed casing so that its operation by the engineer may be detected. The contactor CC is also used to re-energize the noncontrol relay NC after it has been cle-ener gized because of the failure of the engineer to properly operate the contacter TC, ali as hereinafter described.

The vehicle brakes may be controlled in any suitable manner by means of any one of a number of well known devices adapted for this purpose. the initiation of an automatic brake application is usually effected by means of some suitable valve, an electro-pneumatic valve lPV has been shown, it being assumed that the de-energization of this valve acts through well known control apparatus to initiate an automatic brake application.

Certain of the vehicle circuits in the present invention are controlled in accordance with the speed at which the vehicle is traveling, and a suitable speed responsive device is provided for this purpose. This speed responsive device may take any suitable form, and as shown, comprises a simple centrifuge Gr of the well known ily-ball type, it being sinned that this centrifuge is driven through suitable mechanical transn'iitting means from an axle of the vehicle. The centrifuge G is provided with a pivotally mounted contact arm 22 which cooperates at certain vehicle speeds with the stationary Contact segments i3 and 74, the operation of the centrifuge G and the contact arm 22 being readily apparent from the disclosure in the drawings.

The restrictive control of the vehicle while ti'..veli1ig` in unequipped or non-train-control territory is accomplished by means of a time element contacter, designated as a whole as T G. In the particular form shown, which may be changed or modified in certain w ys, tho contacter comprises an outer casing 23 provided with a locked or sealed cover 24. Suitably secured within the casing 23 is an inner casing 25, preferably of cylindrical form and having a partition or barrier wall 2G extending transversely across the center thereof. The upper chamber 27 of the inner casing 25 is provided with a piston 23 of the well known type used in pump construction and having a flexible portion near the edges thereof as shown, so that liquid contained in the chamber 2T may pass downwardly past the edges of the piston 23, but may not pass upwardly past this piston. The piston 23 connected to an operating plunger 29 which extends through the cover at) of the inner casing 25 and cover 24 of the outer casing 23 as shown, This plunger 29 is provided with an enlarged handle 3l at its upper end, a spring 32 being provided to normally,7 maintain the plunger 29 together with the piston 23 in their extreme upper positions. The barrier wall or partition 26 is provided with a suitable check valve 33 of well known construction, which permits fluid flow from the upper chamber 27 of the inner casing 26 to the lower chamber 34 thereof, but prevents fluid flew from the lower chamber 34 to the upper chainber 27. A piston 35 is provided in the lower chamber 34, being normally biased to its upper position by the spring 3G as shown. This piston 35 is provided with a leak port 37 which permits a limited flow of fluid through this piston. The piston 35 is carriedby a rod 33 which passes through the lower wall 39 of the inner casing 25 and through the lower wall of the outer casing 23, a packing joint 40 of well known construction being provided to permit the sliding operation of this rod 33 through the lower wall of the outer casing and to prevent the leakage of fluid from the outer casing. The rod 3S is provided with two movable contact member 4l and 42 which cooperate with pairs of suitable stationary contacts 43 and 44 to close control circuits as hereinafter described. The inner and outer casings 23 and 25 are filled to the level shovui with a suitable fluid such as castor oil, glycerine, or the like, this fluid being admitted to the upper and lower chambers cf the inner casing through the openings 4T and 48 in the upper and lower walls thereof.

F rom this description of the time element contacter TG, it will be readily understood that, when the handle 3l is depressed, the fluid contained in the upper chamber 27 of the inner casing 25 is forced through the check valve 33 to the lower chamber 34, forcing the piston 35, with its rod 38, to the lower position against the opposition of the spring 36. As the handle 31 is released and the upper piston 28 resumes its normal upper position, the fluid forced into the lower chamber 34 is trapped therein by the check valve 33; and the spring 36 slowly forces the piston 35 npwardly as the fluid passes through the leak port 37 in this piston 35. Thus succes ive operations of the handle 3l of the contactor TC serve to maintain the rod 38 with its contacts 4l and 42 in their lower position where the stationary contacts 43 and 44 are connected by the movable contacts 4l and 42, and a control circuit is maintained closed as hereinafter described. If the engineer attempts to defeat the operation of the control apparatus by holding or securing the handle 3l of the contacter TC in its lower position, the lower piston 35 operates in the manner described and the contacts 4l and 42 disengage their stationary contacts after a predeterminet time interval.

A warning signal W, which may be a whistle, bell or other suitable device, is operated upon closing of the contacts 41-43, and acts to give a warning or indication a few seconds before the piston 35 nearly reaches its uppermost posit-ion and the contacts 42-44 open. It is to be understood that the whistle 7 is sounded momentarily during each downward movement of 38.

peratoa (Fig. 1

All of the devices and circuits havebeen shown in their normal operating condition,

that is, with a train proceeding in the train control territory under clear traffic conditions and with all circuits and devices properly energized. For the sake of simplicity the letters B and C have been used to denote the opposite terminals of a suitable source of electrical energy, such as a storage battery or turbogenerator.

With a train proceeding in a block in which clear traffic conditions exist, that is, with no other train in the block in which the train under consideration is located, or in the first block in advance thereof, train control current flows in the track rails in front of the train, and induces voltages in the receiving' coils 16 and 17, which voltages are amplified by the amplifier A and energize the main relay MR. With the main relay MR energized, a circuit is completed forenergizing the electro-pneumatic valve EPV, which circuit may be traced as follows z-from t-he battery terminal B, contact finger 50 and front contacts of the main relay MR, wires 51 and 52, and the winding of the electro-pneumatic valve EPV to the battery terminal C. With the electro-pneumatic valve EBV thus energized, the train may proceed in clear territory without automatic restriction.

When the train under consideration enters a block in which caution traffic conditions eX- ist, that is, the first block in the rear of the block in which another train is located, no train control current flows in the track rails by reason of the operation of the track relay in the occupied block as described above. The main relay MR is therefore de-energized and retracts its contact fingers d50 and 53. The same is true if the train enters an occupied or danger block. The retraction of the contact finger 50 causes the de-energization of the electro-pneumatic valve EPV, breaking the energizing circuit traced above and causing an automatic brake application, which brings the train to a stop, or limits its speed to a predetermined value through any suitable control apparatus. It is contemplated that, after such an automatic brake application in a caution or a danger block, the train is permitted to proceed either after a reset, manual or automatic, when brought to a stop, or without such reset at a limited speed, the apparatus for accomplishing these or other train controling functions, as desired, being well known to those skilled in the art and requiring no special illlustration and description.

Considering now the operation of a train in unequipped sections of trackway, assume that a train approaches the entrance end of the excess energy section J at the entrance to unequipped territory. The engineer is advised of the fact that he is about to enter nontrain-control territory by means of his knowledge of the route or by some suitable wayside indication, and as the train enters the excess energy section J, he depresses the non-control button NB. The actuation of the non-control button NB opens a circuit which normally shunts the resistance unit 19, the shunting circuit being traceable as follows z-from the amplifier A, wires 54 and 55, front Contact and contact .finger 2l of the non-control button NB, and wires 5G and 57 to the main relay MR. As an excess amount of energy flows in the track rails of the seetion J, the insertion of the resistance unit 19 into the input circuit of the main relay MR does not cause the deenergization thereof, the value of this excess energy being sufcient to counteract the effect of the resistance unit 1).

lith the non-control button NB depressed and the main relay MR energized, a pick-up circuit for the non-control relay NC is completed which circuit may be traced as follows from the battery terminal B, contact finger 53 and front contact of the main relay MR, wire 58, contact finger 20 and back contact of the non-control button NB, wires 59, and 6l and the winding of the non-control relay NC to the battery terminal C. The engineer maintains the non-control button NB depressed while the train passes through the excess energy section J, and just before entering the first block K in the unequipped territory, he depresses the time element contactor TC, the contacts 42-44 of which contacter remain in circuit closing position for a predetermined interval of time as described above, say for example, two minutes.

lVith the lower piston 35 of the time element contacter in its lower or actuated position, a stick circuit for the non-control relay is completed as soon as the vehicle enters the unequipped block K and the main relay is cle-energized, this circuit being traceable as follows :-from the battery terminal B, Contact finger 53 and back contact of the main relay MR, wires 62 and 63, stationary contact 44, movable contact 42 and stationary Contact 44 of the time element contacter TC, wires 64 and 65, contactfinger GG and front contact of the non-control relay NC, wires 67 and 61, and the winding of the relay NC to the battery terminal C. The relay N C is sufficiently slow to drop, to remain up during the time elapsing between break of its pick@ up circuit, and make of its stick-up circuit.

With the non-control relay NC energized, a circuit for maintaining the electro-pneumatic valve EPV energized is completed, which circuit may be traced as follows from the battery terminal B, front contact and Contact finger 68 of the non-control relay NC, wires 69 and 52, and the winding of the electropneumatic valve EPV to the battery terminal C.

With the non-control relay NC energized, a n0n-control cab signal N of some suitable type is energized to indicate that the train is proceeding in unequipped territory, the circuit for energizing this signal being completed through the contact finger` 70 and front contact ot the non-control relay NG as clearly shown in the drawings.

l/Vith the electro-pneumatic valve EPV energized, the tra-in may proceed for a certain time in non-control territory without automatic restriction. After a given period of time has elapsed, the piston 350i the time element contacter TC is littedby the spring 36 to a position at which the movablecontact 4l engages its stationary contacts 43, thus completing an energizing circuit tor the warning signal WV, which circuit is obvious from the drawings. The operation ot the warning signal YW informs the engineer that he must again actuate the time element contactor TC. It the engineer immediately depresses the handle 3l of the contactor TC, the piston is again depressed and the rod 38 is moved to its lowest position, the stick circuit for the non-control relay NC being maintained closed, and the electro-pneumatic valve EPV maintained energized, so that the train may proceed without restrictiontor another predetermined time interval. This operation of the time element contactor TC must be repeated at successive intervals of time while the train progresses through unequipped territory, (and of course, must have been in contact making position at the time the train passed into non-train control territory) it being assumed that the proper operation of this contactoi serves to show that the engineer is alive, alert and aware of the -tact that he is proceedingwithout the protection of the automatic equipment.

liould the engineer fail to operate the time element contactor TC within" the predeter mined time interval, the stick circuit for the nonscontrol relay NC is broken by the disengageii'ient ot the stationary contacts 44 with the movable' contact 42, and the non-control relay NC is cle-energized, causing the, decnergization ot the eleCtiopneumatic valve RFV and initiating a restrictive automatic brake application. The noncontrol relay NG contactor CC and a circuit which is obvious trein the drawings, the stick circuit for the .non-control relay NC being completed as described above; To do this, however, the engineer must break the seal preferablyassociated with this cut-out contactor CC, or register Ahe operation on a counter or recorder.

l t is considered that it' the Jtrain is proceedat a low speed in the unequipped`territory no successive acknowledgment should be re quired, this low speed being evidence of the 'tact that the engineer is properly controlling the train. For this purpose an alternative stick circuit for the non-control relay NC is maintained closed so long as the train speed is less than a predetermined low limit, this alternative stick circuit being traceable as fellows ifrnm the battery terminal B, coninay be re-energized through the cut-out tact linger 53 and back contact ot the main relay MR, wires 62 and 71, stationary contact 73, movable contact 22 and stationary contact 74 ot the centrifuge Gr, wires 72 and 65, contact finger 66 and front contact of noncontrel relayNC, wires 67 and 6l and the winding of the relay NC to the battery terminal C. W'ith the stick circuit just traced completed, the vehicle may proceed in the unequipped territory without further operation et the time element contactoi TC so long as the train speed is maintained below a predetermined low speed value, preferably about twenty miles per hour. Also, it the train stops, as at a station or siding, in non-control territory, the low speed contacts 2274 are closed, and the contacter TC need not be operated.

When the train under consideration reenters the section of trackway which is equipped for automatic train control, the main relay MR is re-energized, either by the usual train control currentiiowing inthe track railsof the lirst equippedblock or by a section of trackway which is permanently energized with train control current. The re-energizat-ion of the main relay MR breaks the stick circuit traced above for the noncontrol relay at its contact linger 53 and back Contact, and non-control relay NC is des energized. The energization of the main relay MR also completes an energizing circuiti for the electro-pneumatic valve EPV through the contact finger and front con tact of this relay, this circuit having been traced above, and the train may then proceed in theI equipped territory under the control of the automatic equipment as hereinbetore described.

lt should be observedtliat the non-control button NB'may notV be used to energize the non-control relay NC and thus to avoid the restriction of the automatic control while the train is traveling in equipped territory for there'ason that the depression of this noncontrol button NB causes the insertion ont the resistance unit'l9 in the energizing circuit tor the main relay MRL The train control cur rent normally flowing in thetrack rails in an equipped block is not suiiicient to cause the eiiergization of the main relay MR with the resistance unit 19 inserted in its input circuit; and for this reason the main relay MR drops, de-energizing the electro-pneumatic valve EPV and causing a brake application if the noncontrol button NB isV depressed at any point except while the vehicle is traversing an excess energy section.

From the description of the system of Fig. l, it is seen that a train control system has been provided in which the repeated operation of ainanual device at predetermined time intervals is required while the train is proceedingin unequipigied territory. It is further evident that if the train speed is below a predetermined safe value or if the train has stopped, this repeated manual act in non-control territory is not required.

Referring now to the modified system shown in Fig. 2, certain devices are shown which are identical with the corresponding devices shown and described in connection With Fig. 1, and to simplify the description, these devices Will be referred to by like reference characters.

In addition to the car-carried equipment of Fig. l, the modified system of Fig. 2 includes apparatus for preventing the initiation of an automatic brake application if the engineers brake valve is in the service position, or if a predetermined brake application is in effect, as evidenced by a predetermined reduction of brake pipe pressure. This apparatus may be termed suppressed braking apparatus, and is similar in construction and operation to the corresponding apparatus shown and described, for example, in the application of C. S. Bushnell, Ser. No. 712,269 tiled May 10, 1924. The engineers brake valve handle has been conventionally represented at llV With Contact fingers and 76, it being assumed that these contacts are operated in some suitable manner in accordance With the operation of the brake valve to engage their stationary contacts 77 and 78 when the valve handle is in its service position. Tivo differential pressure cylinders 79 and 80 are provided, having flexible diaphragms 81 and 82 respectively secured to their adjacent ends as shown. A lever 83 is pivoted at the point 84 between the diaphragms 81 and 82, and is provided with a cross member 85 rigidly secured thereto and of a length to bear against both of the diaphragms 81 and 82. A movable contact linger 86 is mounted adjacent the free end of the lever 83, this finger being arranged to engage its stationary contact 87 when the lever 83 is moved to the right. A spring 88 is mounted in the cylinder 79, normally biasing the diaphragme 81 and 82 and the lever 83 to the left hand position as shown, the tension of this spring being adjustable by lneans of a screw 89. The cylinder 80 is connected through an expansion reservoir 90 to an electro-pneumatic valve 91, this valve being norn'ially (lc-energized and when in the le-energized position actingI to connect the cylinder 8() and the reservoir 9() to the brake pipe BP of the usual brake equipment. The connection from the brake pipe to the reservoir 90 is preferably provided With a restricted feed port, so that the pressure builds up in the reservoir at about the same rate as the auxiliary reservoirs, namely about a pound a second. The cylinder 79 is connected by the pipe 92 to the equalizing reservoir of the air brake equipment.

When the engineers brake valve BV is moved to its service position, the movable contact finger 7 5 engages its stationary contact 77, completing an energizing circuit for the valve 91, thus causing this valve to close and to trap brake pipe pressure in the cylinder 8O and the reservoir 90. As the brake pipe pressure is reduced through the engineers brake valve in its service position, the equalizing reservoir pressure is also reduced, and when a predetermined reduction has been made, the trapped initial brake pipe pressure in the cylinder 80 and the reservoir 90 causes the diaphragm 82 to move to the right against the resistance of the spring 88, the amount by which the equalizing reservoir pressure must be reduced below the initial brake pipe pressure being determined by the tension ot the spring 88. As the lever 83 moves to the right it closes the contacts 86 and 87 completing a control circuit as hereinafter described. Thus a predetermined reduction in brake pipe pressure, representing a predetermined brake application, results in the closing of the contacts 86 and 87, Which contacts remain closed until the brake pipe recharged to release the brakes.

In the system shown in Fig. 2, the vehicle brakes are assumed to be controlled in some suitable manner by the electro-pneumatic valve EPVl, this valve being slightly difierent in construction from the electro-pneumatic valve EPV shown and described in Fig. 1. The valve EPVl shoivn in Fig. 2 is provided With a contact operating rod 101 carrying a movable contact member 99, it being understood that the rod 101 together with the contact member 99 is moved to a position to connect the stationary contacts 98 and 100 .vhen the valve EPVl is energized.

Operation, (Fig.

Although only the car-carried apparatus of a train control system has been shown in Fig. 2, it is assumed that this apparatus is to be used with trackivay equipment such as that shown in connection with Fig. 1, the construction and operation of such trackivay equipment being identical with that of the apparatus of Fig. 1.

Considering first the operation of the system shown in Fig. 2, with a train traveling under clear traffic conditions over trackway which is equipped for automatic train control, voltages are induced in the receiving coils 1G and 17, are amplified by the amplifier A and cause the energization of the main relay MR through an obvious circuit. The energization of the main relay MR causes its contact fingers 53 and 50 to be attracted, thus energizing the electro-pneumatic valve RFV]- through a circuit which may be traced as follows from the battery terminal l), contact finger' 50 and front contact of the main relay MR, Wires 94 and 95, the winding of the electro-pneumatic valve EPVI, Wires 9G and 97, stationary contact 98 and movable stick cont-act 99 and stationary contact 100 of the electro-pneumatic valve EPV1 to the battery terminal C. With the valve EPV1 thus energized, the train under consideration may proceed without automatic restriction in the clear territory.

Considering now the operation of the train under consideration upon the entrance into a block in which caution trafiic conditions eX- ist, it being assumed that the engineer is on the alert, has seen and recognized the indication of the wayside signal at the entrance to such caution block and desires to operate the automatic apparatus properly to avoid automatic brake application. As the re ceiving coils 16 and 17 pass over the insulating joints between the clear and the caution block, no voltages are induced therein, and the main relay MR is cle-energized. Just before the de-energization of the main relay MR, assuming the train to have a speed above the low speed limit of twenty miles per hour, the engineer, in order to avoid an automatic brake application and a penalty as hereinafter described, places his brake valve BV in the service position, holding the valve in this position. until a predetermined service reduction in brake pipe pressure is made, the amount of this reduction being indicated by the usual pressure gauge of the well known air brake equipment. If the engineers brake valve is in the service position as the train under consideration enters the caution block and the main relay MR is deenergized, a circuit is completed for maintaining the electro-pneumatic valve EPVl energized, which circuit may be traced as follows z-'from the battery terminal B, movable contact finger 7 6 and stationary contact 78 ot the engineers brake valve BV, wires 102 and 95, winding of the electro-pneumatic valve EPVl, wires 96 and 97, stationary contact 98, movable contact 99 and stationary contact 100 to the battery terminal C. If a predetermined service` reduction in brake pipe pressure has been made before the caution block is entered and the engineer has returned his brake to the lap position, the initial brake pipe pressure trapped in the reservoir and the cylinder 80 moves the diaphragme 81 and 82 together' with the lever 88 to the right, closing the contacts 86 and 87 as described above, and an alternative energizing circuitfor the electro-piieuinatic valve EPV1 is completed, which circuit may be traced as follows 'from the battery terminal B, stationary contact 87 and contact finger 86, wires 103, 104, 105 and 95, winding of the electro-pneumatic valve EPVl, wires 96 and 97, stationary contact 98, movable contact 99 and stationary contact 100 to the battery terminal C. With a service brake application in effect, the train speed is reduced as the train proceeds in the caution block, and when the speed has been reduced to a safe low value, assumed to be twenty miles per hour, the engineer may recharge the brake pipe and release the vehicle brakes provided he first operates the acknowledging time element contacter TC. With the train speed below the low speed limit and the acknowledging contactor TC in its operated condition, a circuit is completed for energizing the acknowledging relay Ack, which circuit may be traced as follows z-from the battery terminal B, stationary contact 44, mov able Contact 42 and stationary contact 44 of. the acknowledging contactor TC, wires 10G and 107, contact segment 108, movable contact 109 and contact segment 110 of the centrifuge G, these contacts being closed at speeds below twenty miles )er hour. wires 111 and 112, and the winding of the acknowledging relay Ac/c to the battery terminal C. lith the acknowledging relay A07@ energized an energizing circuit for the electro-pneumatic valve EPVl is completed, which circuit inay be traced as follows :-from the battery terminal B, contact finger 113 and front contact of the acknowledging relay Ack, wires 114, and 95, winding ot the electro-pneumatic valve EPVl, wires 96 and 97, stationary contact 98 movable contact 99 and stationary contact 100 to the battery terminal C. Vith the electro-pneumatic: valve EPVJ- thus energized, the train may proceed at or below the assumed low speed limit of twenty miles per hour through the remainder of the caution block provided the engineer operates the time element acknowledging contactor TC at predetermined time intervals to maintain the energizing circuit for the acknowledging relay A010 closed, the warning signal XV being initiated to inform the engineer that the contactor TC must a gaini be depressed at successive intervals as described in connection with the description of Fig. 1.

If, on entering a caution block, the train speed be within the low speed limit of 20 miles per hour, intermittent operation of the time contactor TC will maintain relay Acli in its picked up condition, and so maintain EPVl energized through an energizing circuit including finger 113 and fron-t point of A070, as traced above.

As the train proceeds from the caution block into the danger or occupied block, theI main relay MR remains de-energized, there,

being no control current flowing in the track rails of the occupied block for the reasons described above. The control apparatus remains in the condition described in connection with the operation in a caution block, and if" the engineer operates the time element contactor TC at predetermined intervals and' maintains the train speed below the low limit' of twenty miles per hour, no automatic brake application is initiated.

If the engineer fails to initiate a service brake application in recogni `on of the caution indication of thc waysrt al upon entering a caution block, no ng' ',r cuit for the electro-pneumatic valve El. completed, and when this valvc is de-encr gized at the contact finger of the main relav MR, due to the deeenergization of this rel" y upon the entrance into the caution block, automatic brake application is initiated and the train is brought to a stop. It should be observed that as soon as the electro-p r- Inatic valve EPV1 is tlc-energized, it retracts its movable contact 99, thus breaking the circuit to the battery tcrn'iinal C through this valve and making it impossible to re-energize the valve by means of the suppres d braking contacts 86 and S7 or the contacts of the acknowledging contact TC. At the train has come to a stop, the movable gment 115 of the centrifuge C engages its siationary contact segments 116 and 117, these contacts being closed at a very low speed, assumed to be one or two miles per hour, and if the engineer at this time operates the acknowledging contacter TC an energizing t cuit for the acknowledging relay Ad; is coinpleted, which circuit may be traced as follows from the battery terminal B, stationary contact 44, movable Contact 42 and stationary Contact 44 of the contacter TC, wires 106 and 107, contact segment 10S, movable contact 109 and contact segment 110 of the centrifuge G, wire 111, wire 112 and winding of the acknowledging relay Ad: to the battery terminal C. The energization of the acknowledging relay Ack completes an energizing circuit for the electro-pneumatic valve EPV1 which circuit is traceable as follows :F` from the battery terminal B, contact finger 113 and front contact of the acknmvledging relay Ack, wires 114, 105 and 95, windingl of the electro-pneumatic valve EPVl, wires 96 and 118, stationary contact segment 117, movable contact 115 and stationary contact segment 116 of the centrifuge Gr to the battery terminal C. Once energized, the electropneumatic valve EPV1 is maintained encrgized through a circuit including the front contactand contact finger 113 of the acknowledging relay Aclc, which circuit has been traced above, and the train may again proceed in the caution block below the low speed limit provided the engineer operates the time element contacter TC at predetermined interi vals as described above to maintain the relay AC.: energized.

If at any time while proceeding in a caution or a danger block the engineer exceeds the low speed limit, assumed to be twenty miles per hour, or fails to operate the time element contactor TC within the prescribed time intervals to maintain its movable contact 42 in engagement with its stationary contacts 43 and 44, the energizing' circuit for the acknowledging relay Ack is broken, this tl il circuit having been traced above, and the encrg'zing circuit for the electro-pneun'iatic valve llPVl is broken at the contact linger 113 and front contact of the relay A073. This de-cncrgization of the electro-pneumatic valve EVl causes a brake application, bringing the train to a stop, when the electro-pneumatic valve may be rie-energized through the two miles per hour centrifuge contact segments 116 and 117 and movable segment 115 as described above.

The fact that the train must be brought to a stop to rc-cnergize the electro-pneumatic valve oncel it has been cle-energized as described above imposes a penalty upon the engineer for a failure to properly obserw and acknowledge unfavorable signal inoications or failure to successively operate the contacter TC at predetermined intervals when traveling under unfavorable traiiic conditions. This penalty is for the purpose of encouraging the engineer to observe closely the indication of the wayside signals and to properly operate the car-carried control apparatus in recognition thereof.

Considering now the operation of the appa ius of Fig. 2 with a train operating over a section of trackway which is unequipped for train control, as the train passes from equipped into unequipped territory the receiv' ig coils 16 and 17 encounter an excess eiiergj/,f loop or section such as the section J ribed in connection with the apparatus of Fig. 1. The engineer, being appriscd of the fact that he is about to enter an unequipped section of trackway by means of his knowledge of the route or by a suitable wayside indication, depresses the non-control push button NB, and so holds it throughout the excess energy zone, thus breaking the siuniting circuit around the resistance unit 19 in the main relay energizing circuit, and closing' a pick-up circuit for the non-control relay NC, these circuits having been traced above in connection with the explanation of 'the operation of the apparatus in Fig. 1. The main relay MR remains energized due to the excess energy inducing voltages in the recciving coils 16 and 17, and the non-control relay l@ is energized. As the train passes into the unequipped section of traclrway, the main relay MR is cle-energized and if at this time the engineer operates the time element contacter TC, an energizing circuit for the acknowledging relay A67: is completed (the non-control relay NC being already picked up) which may be traced as follows :from the battery terminal B, stationary contacts 44 and movable contact 42 of the contacter TC, wires 1,06 and 123, front contact and contact iinger 124 of the non-control. relay NC, wires 125 and 112 and the winding of the acknowledging relay Acli; to the battery terminal C. A stick circuit for the non-control relay NC is thereby completed, when MR releases, which circuit may be traced as follows-from the battery terminal B, contact finger 53 and back contact of main relay MR, wire 119, contact finger 120 and front contact of acknowledging relay Ack, wire 121, Contact linger 122 and front contact of non-control relay NC, wires 123 and 01 to the winding of the noncontrol relay NC and to the battery terminal C.

Relay NG designed to be slow to release, in the same manner as described in connection with Fig. 1, and for the same reason. With the non-control relay NC energized, the noncontrol cab signal N is energized through the contact finger 126 and front contact of the relay NC, this circuit being obvious from the drawings. The electro pneumatic valve EPVl is maintained energized through a circuit which may be traced as follows z--from the battery terminal B, contact linger 127 and front contact of the non-control relay NC, wires 128, 104, 105 and 95, winding of the electro-pneumatic valve EPVl, wires 96 and 97, stationary Contact. 9S, movable Contact 99 and stationary contact 100 of the electropneumatic valve EPVl to the battery terminal C. Nith the electro-pneumatic valve thus energized, the train under considera-tion may proceed in the unequipped section of trackwa-y without restriction so long as the acanowledging relay Ac/c is maintained energized through the successive operation of the time element contactor TC as described above. ff, while the train is operating in the un equipped territory, the engineer places the brake valve BV in its service position or initiates a service brake application, an alternative energizing circuit for the electro-pneumatic valve EPVl is completed through the contacts 8S and 87, this circuit having been traced above, and the time element contactor TC need not be operated at successive intervals to prevent an automatic brake application so long as the contacts 86 and 87 are maintained closed.

It' the engineer fails to operate the time ele ment contactor TC at predetermined intervals while proceedingA in unequipped territory with no manual brake application initiated and with. the brake valve in its lap or running position, the acknowledging relay Aff/l: is de-energized at the contacts 42, 43 and 44 of the time element contactor TC, the energizing circuit for the electro-pneumatic valve EPVl is broken at the contact linger 1125 and front contact of the acknowledging relay Ack, and an automatic brake application results, bringing the train to a stop before the electro-pneumatic valve EPVl may be riz-energized.

This re-energization of the electro-pneumatic valve EPVl in non-train-control territory may be effected in either one of two ways. After the train has been brought substantially to a stop, the two mile per hour stationary contacts 116 and 117 of the centrifuge G are engaged by the movable contact segment 115, and if at this time the time element contactor TC is operated, energizing the acknowledging relay A076 through the twenty mile per hour contacts 108, 109 and 110 of the centrifuge G, the electro-pneumatic valve EPVl is energized through a circuit including the front contact of the acknowledging relay A076 andthe two mile per hour contacts of the centrifuge G, all these circuits having been traced above. Once energized the electro-penumatic valve EPVl is .maintained energized through its stick con tacts 98, 99 and 100, and the contact 113 of the acknowledging relay Ac/c. The acknowledging relay is maintained energized only so long as the vehicle speed remains below twenty miles per hour, (unless NC has been re-energized, and this relay NG cannot be picked up in non-train control territory without operating contactor CC and incurring a resulting penalty) and the contactor TC is operated at predetermined intervals, the progress of the train being therefore restricted as a result of the engineers failure toy properly acknowledge at predetermined intervals in non-train-control territory.

If the engineer wishes to proceed in the unequipped territory without restriction as to speed, he must re-energize the non-control relay NC by operating the cut-out contactor CC, thus completing an energizing circuit for the non-control relay which may be traced as follows z-from the battery terminal B, contact finger 131 and stationary contact of the cut-out contactor CC, wires 129, and 61, and the winding of the non-control relay NC to the battery terminal C. If the acknowledging relay A070 has been energized by the operation of the time element contactor TC, a stick circuit for the non-control relay is completed through the back contact and contact inger 53 of the main relay MR, and the contact finger 120 and the front contact of the acknowledging relay A670, this circuit having been traced above. As pointed out above, the cut-out contactor CC is provided with a lock, seal or recording mechanism, so that its operation by the engineer may be detected by the train conductor, despatcher or other oliicial, and in this manner, the operation of this contactor acts as a penalty on the engineer for his failure to properly operate the contactor TC in nontrain-control territory.

The engineer thus has the option of taking either one of two penalties if he fails to opcrate the time element contactor TC within the prescribed time intervals while operating in unequipped territory, the penalty of proceeding within a low speed limit or the penalty of operating the cut-out contactor CC, and the knowledge that these penalties will be imposed encourages him to remain on the alert, to properly operate the contacter TC in non-train-control territory and in this manner to manifest his vigilance in his control of the train.

As the present invention has been desciibed in connection with a specific system ot' train control embodying certain specific devices and apparatus .itshould be clearlv understood that the invention is not liinit-ed in its scope to the particular means shown and described in connection therewith and that many modifications and changes might be made without departing from the spirit ot the invention as defined by the appended claims.

What it is desired to be secured by Letters Patent is:

1. In an automatic tain control system for railways having sections of their track- Way equipped for automatic train control and sections not so equipped, vehicle-carried apparatus comprising, a device for causing an automatic brake application when initiated, means for controlling the initiation of said device in accordance with tic-allie conditions ahead when the vehicle is traveling in said equipped sections of trackway, and means for preventing the initiation of said device while the vehicle is traveling in said unequipped sections of trackway provided a manually operable device is operated at predetermined time intervals.

2. In an automatic train control system for railways having sections oi their tract:- way equipped for automatic train control and sections not so equipped, vehicle-carried apparatus comprising, a normally energized device for initiating a brake application when de-energized, means for controlling the energization of said device iii accordance with tratlie conditions ahead when thevehicle is travelingr in said equipped sections of trackwav, a control means, operable only when the vehicle enters said unequipped sections of trackway for maintaining' said dcvice energized, and a manually operable means, acting it operated at predetermined time intervals 'lo maintain said control nicnas operated while the vehicle is traveling in said unequipped sections of trackway.

2l. In an automatic train control system for railways having sections of their track- Way equipped for automatic train control and sections not so equipped, vehicle-carried apparatus comprising, a nprmally energized brake applying device acting when de-energized to initiate an automatic brake application, means for maintaining said device energized when the vehicle is traveling in said equipped sections ot trackway under favorable traffic conditions ahead7 means tor mairtaining said device energized when said vehicle is traveling in said equipped sections ot trackway under unfavorable traitic conditions ahead and when said vehicle is traveling in said unequipped sections ot trackway coinprising, a relay acting when energized to maintain said brake applying device `energized, and means for energizing said relay provided the vehicle speed is maintained below a predetermined low speed limit and a manually operable contacter is operated at predetermined time intervals.

l. In an automatic train control system for railways having sections of their trackway equipped tor automatic train control and sections not so equipped, vehicle-carried apparatus comprising, a normally energized brake applying device acting to initiate an automatic brake application when de-energized, means for maintaining said device energized when the vehicle is traveling in said equipped sections of trackway under favorable tratiic conditions ahead, means for maintaining said brake applying device energized when the vehicle is travelingl in said equipped sections of t-rackway under untavorable traiiic conditions ahead comprising an acknowledging relay acting when energized to maintain .said brake applying device energized and an energizingT circuit for said acknowledging relay includingl in series contacts closed only if the vehicle speed is below a predetermined low limit and contacts closed only if a manually operable device is operated at predetermined time intervals, and means for maintaining said brake applying device energized when the vehicle is tiavelin in said unequipped sections ot trackway comprising said acknowledging relay and including contacts closed only it said manually operable device is operated at said predetermined time intervals.

5. In an automatic train control system for railways having sections or" their trackvay equipped for automatic train control and sections not so equipped, vehicle-carried apparatus comprising, a normally energized device for applying the vehicle brakes when fle-energized, means tor maintainingsaid dcvice energized in accordance with influences received from the traciiway when the vehicle is travclingin said equipped sections olE trackway under favorable tratiic conditions ahead, means tor maintaining said brake applying device energized when the vehicle is traveling in said equipped sections under unfavorable trailic conditions ahead comprising, contacts closed only if the engineers brake valve is in the service position and a further energizing circuit ior said brake applying device including contacts closed it a predetermined brake application is in effect, means for maintaining said brake applying device energized when the vehicle is traveling in said unequipped sections ot trackway comprising` an acknowledging relay acting when energized to maintain said brake applying devici` energized and an energizing circuit tor said acknowledging relay including contacts llt] lli!

closed only it the vehicle speed is below a predetermined low speed limit in series with contacts maintained closed only it a manually operable device is operated at predetermined time intervals.

G. ln an automatic train control system for railways having` sections of their traclrway equipped for automatic train control and sect-ions not so equipped, vehicle-carried apparatus comprising, an automatic brake applying device, means i'or preventing the initiation ot said device under favorable tratic conditions ahead when the vehicle is travcling in said equipped sections of traclcway, means tor preventing the initiation of said device under unfavorable trailic conditions ahead in said equipped sections ot traclrway provided a manually operable device is operated at predeterminel time intervals and also provided the vehicle speed is below a predetermined low limit, and means for preventing the initiation ot said brale apply'ng device when the vehicle traveling in said unequipped sections oi" traekway provided said manually operable device is operated at predetermined time intervals regardless of the vehicle speed.

7. In an automatic train control system for railways having sections oi their traclnvay `uipped tor automatic train control and sections not so equipped, vehicle-carried apparatus comprising, a device ior applying the vehicle brakes when initiated, means 'ior preventing the initiation ot said brake applying device in response to influences corresponding to tavorz-ible trailic conditions ahead received from the traer-:Way in said equipped sections, means for preventing the initiation of said device when no influences corresponding to favorable traiiic conditions are received in said eduipped sections provided the vehicle speed belen a predetermined low speed limit and a manually operable device is operateo. predetermined time intervals, means tor preventing the initiation ot said brake apolyin g device when the vehicle is traveling in d unequippcd sections ot traclrivay provided said manually operable device is operated at said predetermined time intervals, and means tor preventing the initiation ot said bralre applying device when the ifeliicle is travelingl in said equipped sections or in said unequipped sections provided the engineers brake valve is in the service position or provided a predetermined brake application is in eilect.

8. ln an automatic train control system tor railways having sections ot their traclnvay equipped tor automatic train control and sections not equipped, vehicle-carried apparatus comprising, a normally energized brake applying device acting when Cle-energized to initiate an automatic brake application, a. main relay energized only when influences corresponding` to favorable trafic conditions are received 'from the traclrivay in said equipped sections and acting when energized to maintain said brake applying device energized, an aclnnowledging` relay acting when energized to maintain said brake an energizing cirapolying device energized,

cu r said aclniowledging relay including` in series speed controlled contacts cl .sed only when the vehicle speed is below a predetermined loiv only it a in-nualiy operable device is operated at predetermined t-ne intervals, a stick relay having a pick-up circuit, means for closing said pick-up circuit oiny at the entrance to said uncquipy ed sections ot traclmvay, al

stick circuit tor stiel; relay maintained closed only when the. vehicle is traveling in said unequipped sections ot traclrivay providing Lid aclniovrledging relay is energized, said st relay acting when energized to eed controlled contacts out et ging relay energizing circuit. 9. ln an automatic train contr l system 'tor railways having see 1 oi' their traclrivay equipped for automatic train control and sections notso equipped, vehicle-carried apparatus comprising, a normally energized bralic applying device acting when de-eergized to initiate an automatic brake application,l a

main relay energized only when influences corresponding to favorable traiic conditions are received from the traclrivay in said equipped sections and acting when energized to maintain said brake applying device enel. gized, an acknowledging relay acting when ing a pick-up circuit, means tor closing said.

pick-up circuit only at the entrance to said nnequipped sections of trackway, a stick ciriior said stiel; relay maintained closed when the vehicle is travelin in said unupped sections ot traclrivay and providing s o acknowledging relay is energized, said stiel; relay acting when energized to shunt said speed controlled contacts out of said acknowledging relay energizing circuit, and 'further means tor maintaining said brake applying device energized said equipped said unequipped sections ot tracirwayhprovided the engineefs brake valve is in its service position or provided a predetermined brake application is in eilect.

l0. In an automatic train control system for railways having` sections ot' their traelrivay equipped for automatic train control and sections not so cguipped, vehicle-carried apparatus comprising, a normally energized electro-magnetic stiel; device acting to inipced limit and contacts closedk tiate an automatic brake application when deenergized, means for maintaining a stick circuit for said stick device closed when the vehicle is traveling in said equipped sections of trackway under kfavorable tral'lie conditions ahead, an acknowledging relay acting when energized to close a stick circuit for said stick device and a circuit for energizing said ac` knowledging relay including low speed contacts closed it the vehicle speed is below a predetermined low speed limit in series with contacts closed if a manually operable device is operated at predetermined time intervals, a stick relay having a pick-up circuit and a stick circuit, means for closing said pick-up circuit through a manually actuable circuit closer only at the entrance to said unequipped sections of trackway, means for maintaining said stick circuit for said stick relay closed only when the vehicle is traveling in said unequipped sections of trackway, said stick relay acting when energized to shunt said low speed contacts from said acxnowledgin relay energizing circuit, and a pick-up circuit for said electro-magnetic stick device including contacts closed only when the vehicle is substantially at a stop and contacts closed only when said acknowledging relay is energized.

11. In an automatic train control system for railways having sections of their trackway equipped for automatic train control and sections not so equipped, vehicle-carried apparatus comprising, a speed-responsive device, a normally energized stick device acting to initiate an automatic brake application when de-energized, means for maintaining a stick circuit for said stick device closed when the vehicle is traveling in said equipped sections of trackway under favorable traflic conditions ahead` an acknowledging relay acting when energized to complete a stick circuit for said stick device and an energizing circuit for said acknowledging relay ineluding contacts of said speed-responsive oevice closed only when the vehicle speed is below a predetermined low limit in series with contacts closed if a manually operable device is operated at predetermined time intervals, a stick relay acting when energized to shunt said low speed contacts of said speed responsive device and having a pick-up circuit and a stick circuit, means' for closing said pick-up circuit for said stick relay only as the vehicle enters said unequipped sections of trackway, means for closing said stick circuit for said stick relay only when the vehicle is traveling in said miequipped sections of trackway, a stick circuit for said normally energized stick device including contacts closed when the engineers brake valve is in the service position, a stic t circuit for said normally energized stick device including contacts closed when a predetermined brake application is in effect, and a pick-up circuit for said normally energized stick deized to nuria won, means for maintaining :said device encrgized when the vehicle is travelingin said equipped sections oit" tracliway under favoraizle tra rondiiions ahead means for maintaining said device enci hielo traveling' in said uneilinipl'ied sections o1! trackway, comprising, a relay acting when energis-:ed maint Ysaid brake applying device cna means for energizing said relay requiring that the vehiclerspeed be maintained bei. a predetermined low :qxeed limit,y and a niannally operable contacter he operated at predetermined time intervals.

l. In an tor railffajfs "'ay equipped sf ltions zint so c:

paratus cen .ftomatic train control and pjed, vehicle-carried api i p a normally energized brake applyino' device acting to initiate an automatic brake applicationV when cle-ener- Igized, means lor inaintainingj;l said device energized when the vehicle traveling in said equipped sections ot trackway under l'avorable trailic conditions` ahead. means for maintaining said brake applying device energized when the vehicle is traveling in said equipped sections ot twickvfay under unfavorable traflic conditions ah Aad con'iprising an acknowledging relay acting when energized to maintain said lnakc applying device energized and an energizing circuit for said. ae` knowledging relay including, in series, contacts clos l only the vehicle speed is below a predeternnned low limit and ccntactf's maintained closed onlv ilE a manually operable device is operated at predetermined time intervals.

f-l. ln an antematic train control system for railwaj/,fs havin sections ci" their track- "ay equipped for ai Yoinatic train control and sections not so equipped, veliicio-carried apmaintain said brake applying device energized and an energizing circuit for said acknowledging relay including, in series, contacts closed only it the vehicle speed is below a predetermined low limit and contacts closed only it' a manually operable device is operated at predetermined time intervals, and means for maintaining said bra-ke applying device energized when the vehicle is traveling in said unequipped sections oit trackway.

15. ln an automatic train control system for railways having sections ot' their trackway equipped for automatic train co trol and sections not so equipped, vehicle-carried apparatus comprising, a device for applying the vehicle brakes when initiated, means 'for preventing the-initiation oi said device when no inliuences corresponding to 'favorable trattic conditions are received in said equipped sections provided the vehicle speed below a predetermined low speed limit and a manually oijierable device is operated at predetermined time intervals, and means tor preventing the initiation ci' said b te applying device when the vehicle traveling in said unequipped sections ot traclrway provided said manually operable device is o perated at said predetermined time intervals.

l't. ln an automatic train control system for railways having sect' ins ot their trackway equipped 'for automatic train control and sections not so equipped, vehicle-carried apparatus comprising, a device 'for applying the vehicle bra-kes when initiated, means for preventing the initiation ot' said device when no intiuences corresponding to favorable ti conditions are received in said equipped sections provided the vehicle speed is below a predetermined lo i speed limit and a manually operable device is operated at predetermined time intervals, means 'tor preventing the initiation ol' said brake applying device when the vehicle is traveling in said unequipped sections of tra-ckway provided said manually operable device is operated at said predetermined time intervals, and means 'tor preventing the initiation ot said 1Drake applying device when the vehicle is traveling in said equipped sections or in said unequipped sections provided the engineers brake valve in the service position or provided a predetermined brake application is in edect.

ll'. ln an automatic train control system i'or railways having sections of their trackway equipped 'for automatic train control and sections not so equipped, vehicle-carried apparatus comprising, a normally energized brake applying device acting when cle-energized to initiate an automatic brake appli- 1 on, a main relay energized only when ins corresprmding to favorable tratlic ,ns are received 'from the trackway in dipped sections and acting when energized to maintain said brake applying device energized, an acknowledging relay having a Contact finger and front point in an energizing circuit 'for said brake applying device, a stick relay having a pick-up circuit, means for closing said pick-up circuit only at the entrance to said unequipped section of traciiway, and a stick circuit for said stick relay including a hack point of said main relay and a front point of said stick relay.

ln an automatic train control system 'for railways having sections ot their trackway equipped for automatic train control and sections not so equipped, vehicle-carried apparatus comprising, a normally energized brake applying device acting when de-energized to initiate an automatic brake application, a main relay energized only when intluences corresponding` to favorable traiic conditi are received Ylfrom the trackway in said equipped sections and acting when energized to maintain said brake applying device energized, an acknowledging relay acting when energized to maintain said brake appl' ng device energized, an energizing circuit tor said acknowledging relay, a stick relay having a pick-up circuit, means for closing 1d pick-up circuit only at the entrance to unequipped sections ot trackway, a

stick circuit for said stick relay maintained closed only when the vehicle is traveling in said unequipped sections oit trackway and providing said acknowledging relay is energized, and further means for maintaining said brake applying device energized in said equipped or said unequipped sections of trackway provided the engineers brake valve is in its service position or provided a predetermined brake application is in effect.

l). ln an automatic train control system for railways havinO sections equipped for automatic train control and sections not so equipped, a device acting when initiated to cause an automatic brake application, means for preventing initiation of said device during travel through train control territory regardless ci tratlic conditions, and means to prevent initiation of said device during travel through non-train-control territory, the last said means including means requiring periodic operation to be eective.

ln an automatic train control system railways having sections equipped for automatic train control and sections not `so equipped, a device acting when initiated to cause an automatic brake application, means Ltr" preventing initiation ot said device durtravel through train control territory re- 1 liess `ot tratlic conditions, and means to prevent initiation of said device during travel through non-train-control territory, the last said means including means requiring periodio operation to be eilective, absence of such periodic operation causing an automatic brake application.

2l. ln an automatic train control system tor railways having sections equipped for i ing travel through train control territory regardless of traflic conditions, and means to prevent initiation of said device during travel through non-train-control territory, the last said means including means requiring periodic operation to be effective, absence of such eriodic operation causing an automatic lirake application, and means to release the brakes after an automatic brake application, the operation of such means to release the I brakes imposing a low maximum speed limit throughout the non-train-control territory.

22. In an automatic train control system for railways having sections equipped for automatic train control and sections not so equipped, a device acting when initiated to cause an automatic brake application, means for preventing initiation of said device during travel through train control territory7 regardless 0f traic conditions, and means to prevent initiation of said device during travel through non-train-control territory, the last said means including means requiring periodic operation to be effective, absence of such eriodic operation causing an automatic Brake application, and means to release the brakes, after an automatic application, re-

uiring the indicating of the occurrence of t e automatic brake application.

23. In an automatic train control system for railways having sections equipped :t'or automatic train control and sections not so equipped, a device acting When initiated to cause an automatic brake application, means for preventing initiation ot' said device during travel through train control territory regardless of traic conditions, and means to prevent initiation of said device during travel through non-train-control territory, the last said means including means requiring periodic operation to be effective, absence of such eriodic operation causing an automatic Erake application, and means to release the brakes after an automatic brake application, such means requiring either the imposing ot a. low maximum speed limit throughout the non-train-control territory, or the indication of the occurrence of said automatic brake application.

24. In train control apparatus of the type involving brake-applying mechanism normally controlled by energy received from the trackway, a relay operating when energized to render said mechanism ineffective, and a stick circuit for said relay including a contact which is open when and only when the speed of the train is above a given value. y

25. In train control apparatus of the type involving brake-applying mechanism normally controlled by energy received from the trackway, a relay operating when energized to render said mechanism ineffective, and tvvo holding circuits for said relay one of which is opened when the apparatus is receiving energy from the trackway and the other of which includes a contact which is open When and only when the speed of the train is above a given value.

26. In train control apparatus ot the type involving brake-applying mechanism normally requiring the constant supply of energ from the trackway to permit the train to proceed at full speed, a normally cle-energized relay operating when energized to render said mechanism ineffective in the absence of such energy, and means for energizing said relay upon entering territory not equipped for supplying such energy, the combination therewith of two holding circuits for said relay one of which is opened when the apparatus is receiving energy from the trackway and the other ot' which includes a contact which is open When and only when the speed of the train is above a given value.

27. In train control apparatus of the type involving brake-applying mechanism normally requiring the constant supply 0f energy from the trackvvay to permit the train to proceed at full speed, a normally cle-energized relay operating when energized to render said mechanism inell'ective in the absence oi such energy, and means for energizing said relay upon entering territory not equipped for supplying such energy, the combination there- With of a stick circuit for said relay including a contact which is open when and only when the speed of the train is above a given value. Y

In testimony whereof I aflix my signature.

NEIL D. PRESTON. 

